“huge embarrassment” and “we. fell. short” were among the subject lines of her campaign emails. Up against the clock, she blasted a 5:08 a.m. email under the subject “are you online?”

“Hi - I’m sorry to email you so early but I just can’t sleep,” wrote Brownley, D-Thousand Oaks. “Our ... deadline is tonight, and we’re still quite a way from hitting our goal. I hate to keep asking again and again, but the only way to get there is with your help.”

The approach apparently works. Brownley’s campaign says it has received more than 10,000 individual contributions from grass-roots supporters this year, most in response to her prolific email program.

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Ahead of periodic reporting cutoffs, voters can receive a relentless stream of mail from candidates for president, Congress, and state and local offices.

In recent years, urgent appeals for online donations have become more common, and in many cases are usurping traditional postage on campaigns. “In the last couple cycles, it’s dramatically increased,” said Stephen J. Kaufman, a political attorney based in Los Angeles.

Dependence on online donations, which can make up 10 percent to 40 percent of a candidate’s total, has campaigns experimenting with catchy subject lines that inspire supporters to open and read them. Lately, a subject line may include emojis (small symbols such as faces or timeclocks), all caps and/or multiple exclamation points. Lists of recipients are sometimes shared or traded by campaigns, though some prefer to have other elected officials reach out to their own supporters to encourage a donation.

Along with being far cheaper to send, the emails allow campaigns to react at a moment’s notice, which can be particularly advantageous. Last month, as the U.S. Supreme Court weighed a case challenging an independent redistricting commission, panels charged with redrawing political boundaries, Republican Rep. Jeff Denham’s campaign sounded the alarm in a fundraising plea to supporters.

“Democrats are eager to take power back,” the email stated. “And with the Supreme Court about to release a ruling on redistricting that could allow the Democrats in Sacramento to redraw our district, we may have an even tougher fight ahead of us than we thought. That’s why it’s more important than ever that we push past our goal of raising $45,000 before the end of the quarter.”

Timely appeals are not limited to candidates. America Rising PAC, a Republican opposition research operation, used Democratic presidential candidate Hillary Clinton’s $45 million haul in three months as a motivator to raise money from conservative followers. The Clinton campaign, they wrote, “know(s) what a threat our research is to her White House dreams, and they are spending massive amounts of money to cover it up.”

Recent fundraising opportunities on the left included the high court’s ruling legalizing same-sex marriages and Republican presidential hopeful Donald Trump’s controversial remarks about Mexican immigrants.

“It’s trying to find the levers that get people excited,” said Brent Blackaby, co-founder of Trilogy Interactive, an online strategy firm that works with Democrats.

That can be especially challenging in lopsided races, or when a party is suspected of being years away from reclaiming power.

“It’s not sexy,” said Greg Berlin, founder of Mothership Strategies, another Democratic firm. “You have to convince supporters why they should give to candidates in the U.S. House, where there is a very small chance of winning the House back.”

Raising money by email, mostly in small increments like $3, $25 and $50, is not a new strategy. Sen. Barbara Boxer, D-Calif., took in about $7.5 million of her $30 million that way in the 2010 race against Republican businesswoman Carly Fiorina, Blackaby said. Boxer’s program is a kind of case study: Between 2004 and 2010, her list of recipients increased by more than 1 million people, to a total of 1.1 million.

It was President Barack Obama’s sophisticated online operation, which reportedly raised nearly $700 million via email for his 2012 re-election, that brought new focus to the area. The campaign tested messages from Obama, first lady Michelle Obama, Vice President Joe Biden and various staff. Subject lines, designed to combat the fact that such emails are often ignored, ranged from the casual “hey” and “wow,” to the friendly “Meet me for dinner,” and ominous “I will be outspent.”

“I will be the first president in modern history to be outspent in his re-election campaign,” read the message from Obama, “if things continue as they have so far.”

His tone was no accident. Don Moore, a professor at UC Berkeley, studied the so-called motivating power of underconfidence. Along with Todd Rogers of Harvard University, he found supporters were more likely to act on an email appeal from a candidate who is narrowly trailing the race. The authors noted that Obama and Republican challenger Mitt Romney more often sent emails reporting they were barely losing than that they were slightly ahead.

“Making supporters feel that their involvement is critical to your success is really important for keeping them motivated,” Moore said in an interview.

In contrast, they discovered that voters who had not yet committed to a specific candidate preferred those who were winning to those who were behind.

In other words “saying ‘it’s close, but we’re losing,’ will continue to go to supporters – and not the general public,” Moore said. “On TV, and elsewhere, (candidates) will continue to sound excessively confident.”

The trend in presidential online fundraising seems to be continuing into 2016. On Friday, Clinton’s campaign email (subject: “Hillary needs you,”) warned that Republican Jeb Bush has raised more than $114 million between his campaign and super PAC. “If that number scares you, good,” Clinton’s email stated, “it should.”

“If people unsubscribe, then campaigns slow down the frequency,” he said. “If they keep making money, they keep sending them.”

While most online fundraising is generated by email, one California official has been successful in politically monetizing his social media presence. Lt. Gov. Gavin Newsom, a gubernatorial candidate in 2018, spent seven years collecting hundreds of thousands of email subscribers, including many outside of the state because of his early support for same-sex marriage and progressive stances on universal health care and paid family leave.

Now he has more than 1 million Twitter followers and several thousand on a handful of other social media accounts.

In the first half of the year, Newsom’s campaign said he raised more than $100,000 alone on Facebook, and more than $300,000 from grass-roots supporters online.

Fundraising is clearly one of the ways it pays dividends. But even more important is that it provides a vast network of passionate people talking to their friends and leveraging their support in a way that grows exponentially.

Spokesman Dan Newman on Lt. Gov. Gavin Newsom’s social media presence

Emails that don’t explicitly ask for donations may invite people to sign a petition, offer a holiday greeting or link to a Web page with another call to action.

California Attorney General Kamala Harris, a U.S. Senate candidate, sent a triumphant email featuring a rainbow flag emoji and “Victory!” after the same-sex marriage ruling, and invited supporters to congratulate the plaintiff. Republican presidential candidate Marco Rubio began a fundraising pitch within days of The New York Times running a pair of unflattering stories about him. It linked to a website on the issue that led with the phrase “Elitist Liberal Media Strikes Again.”

It’s always helpful to have a boogeyman to run against and feature prominently to donors, said Ryan Waite of Campaign Solutions, a full-service digital firm representing Republicans. Yet the overarching goal is to be authentic and not create “artificial motivators,” Waite said.

“Depending on the campaign, it’s the candidate who is providing the voice and the types of things that are being talked about,” he said.

The slew of insistent appeals also masks a broader conversation, Blackaby said. He described a healthy debate among political practitioners that comes down to their campaigns not losing sight of their long-term strategy by burning out donors.

“You may not go as far, and you may leave money on table,” he said. “But your list is healthier, and brand is left in better shape.”